1. Field of the Invention
The invention relates to a method for producing a functional unit with a gas converter and a flame ionization detector. Furthermore, the invention relates to a functional unit having a gas converter and a flame ionization detector. The gas converter is used here, in particular, at least partially for transforming a gas or a gas mixture as medium to be converted or transformed.
2. Description of Related Art
Microsystems technology is used for producing structures or components with small-scale dimensions.
In low temperature co-fired ceramics (LTCC), un-sintered—so-called green—ceramic sheets are individually structured, stacked, laminated (laminating generally meaning the joining of layers by means of adhesives) and subjected to a sinter profile at a maximum temperature between ca. 850° C. and 900° C. The LTCC method differs from the production of high temperature co-fired ceramics (HTCC) in the maximum temperatures occurring during sintering, where sintering occurs at temperatures between 1600° C. and 1800° C. Thick film hybrid technologies are also known, wherein conductor paths or resistors are applied to previously-sintered ceramic substrates using screen printing. If the printed carrier is sintered, the applied pastes melt into layers. Then, discrete components are possibly mounted.
One area of use for microsystems technology is, for example, the production of flame ionization detectors. Hydrocarbons are ionized in a hydrogen flame in flame ionization detectors (FID). The flow of ions is, then, a measure for the organic carbon content of the sample to be tested.
A description of a flame ionization detector can be found in International Patent Application Publication WO 2009/036854 A1 and corresponding U.S. Pat. No. 8,305,086 B2. The description of a counter-flow combustor in International Patent Application Publication WO 2011/015285 A2, that corresponds to U.S. Patent Application Publication 2012/0141946 A1, or a counter-flow combustor for a flame ionization detector as disclosed in International Patent Application Publication WO 2012/055835 A1 are relevant in this context.
A method for producing a flame ionization detector can be seen in commonly owned U.S. Patent Application Publication 2014/0035593 A1.
Catalytic gas converters or gas transformers—in part as a preliminary stage—are used in operating flame ionization detectors.
If normal, ambient air is used as the air for sintering, then traces of organic compounds are transformed by means of thermal catalysis in CO2. This, for example, occurs in that sintering air is drawn in from the surroundings via a catalyzer.
Since methane is further present in the air in relatively high concentrations as a trace gas (in part up to 1800 ppb as opposed to 1 ppb for other hydrocarbons), a difference is made between the entire hydrocarbon content and the methane hydrocarbon content. In order to determine the methane hydrocarbon content, the remaining organic compounds are initially removed by means of catalytic oxidation.
Furthermore, carbon monoxide CO and carbon dioxide CO2 can be quantified by means of catalytic methanation, even though flame ionization detectors are principally not sensitive to these compounds. The catalytic methanation, thereby occurs by adding hydrogen at a temperature between 350 and 370° C. following this sequence:CO+3H2→CH4+H2O and CO2+4H2→CH4+2H2O.
This, thus, demonstrates the great advantage of the use of gas converters in conjunction with flame ionization detectors.
Miniaturized converters for transforming liquid methanol into hydrogen for fuel cells, which consist of multi-layer ceramics, can, for example, be seen in the application publications U.S. Patent Application Publication 2007/0154367 A1 or WO 03/088390 A2 corresponds to U.S. Patent Application Publication 2003/0194363 A1.
Different materials for catalyzers for air treatment are disclosed, for example, in German Patent Application DE 691 17 048 A1 and corresponding U.S. Pat. No. 5,292,479.
Catalyzers for producing nanotubes for a gas chromatograph are disclosed, for example, in U.S. Patent Application Publication 2007/0084346 A1.
A difficulty in the use of flame ionization detectors and gas converters, which are characterized overall by their interaction as functional unit, lies in the type of arrangement and connection of components. For example, a safe transmission for the gas converted by the gas converter to the detector must be implemented. Accordingly, this increases the demands on the connections of the detector or converter. Furthermore, sufficient safety must be ensured when dangerous media are used.